DE2923362A1 - ELECTRONIC CONTROL CIRCUIT FOR TAPE RECORDER AND TAPE PLAYBACK DEVICES - Google Patents

Description

SB5P-1957

Electronic control circuit for tape recorders and players

The invention relates to an electronic control circuit for tape recording and tape playback devices with forward and reverse operation, the mechanical actuation of the reversal of the transport direction of the tape is done with the help of a relay.

Such an electronic control circuit is intended to achieve that both in the recording and in the playback mode the tape can be driven forward and backward in such a way that both a recording and a playback of the forward and backward the program assigned to the return is possible without the tape having to be turned over. One such control is especially intended for tape recorders and playback devices, who work with so-called cassettes, so that for a Cassette two programs, one in the forward and the other in the reverse, can be provided. With such Tape recorders and playback devices allow the

reversal

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Reverse the direction of transport mechanically with the aid of at least one relay. Also ejecting the The cassette is usually controlled automatically with the help of a relay, whereby the cassette is automatically in the operating position and can be ejected from this at the end of the recording or playback.

The invention is based on the object of the previous necessary mechanical control for reversing the tape transport direction and, if necessary, for ejecting the cassette eliminate them and replace them with an electronic control system that is simply constructed and therefore very economical too realize is.

According to the invention, this object is achieved in that a detector for the tape disk rotation provides the logic on the output side Signal level 0 or 1 as a function of the rest position or the rotation of the belt plate provides that the detector has a logic level is connected downstream, which on the output side is the logical signal level 0 or 1 delivers, depending on whether the belt plate was held after a previous running operation or a standstill operation and that a monostable multivibrator responds to the output signal of the logic stage and on the output side for every transition from signal level 1 to signal level 0, a control pulse is sent to the relay to reverse the direction of tape transport supplies, whereby the tape transport direction is always switched when the tape plate is in an end position of the Tape comes to a standstill,

According to a further embodiment of the invention, it is provided

that

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that there is an eject relay that enables mechanical ejection of the cassette as a function of a control pulse that controls a 2-bit binary counter as a function of the

Output signal of the logic level delivers when a Transition from signal level 1 to signal level 0 takes place and that after two switchings of the tape transport direction Cassette is ejected.

Further refinements of the invention are the subject matter of further ones Claims.

With the measures of the invention it is possible to record a tape record and tape player to electronically control both forward and reverse operation, with both a Single program operation as well as continuous program operation is possible in a simple manner.

The advantages and features of the invention also emerge from the following description of an exemplary embodiment in FIG Connection with the claims and the drawing. Show it:

Fig. 1 is a block diagram of the electronic

System according to the invention;

Figures 2 and 3 are circuit diagrams of the electronic system

according to FIG. 1;

Fig. 4 is a timing diagram from which the temporal

Dependence of different waveforms emerges which in the circuit

according to

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2 and 3 occur.

The electronic system according to FIG. 1 comprises a detector 1 with which the rotation of the disk receiving the tape is detected is and which from the output side, depending on the resting or moving state of the disc 20, a logic signal level 0 or provides. A first logic level 2 supplies a logic signal level 1 or 0 on the output side, depending on whether the disk is 20 was stopped from the rotating state or the stopping was caused in the case of a stationary disk. A monostable Multivibrator 3 responds to the output signals of the first logic level 2 and in turn delivers a pulse at the output for each transition from the input signal level 1 to the Signal level 0, which controls a relay Rl via a buffer transistor 21 for reversing the transport direction of the tape. That Relay Rl reacts to every control pulse that causes a reversal of the transport direction of the tape.

A first switch stage 4 as well as a second switch stage 5 and a switch stage 6 with a spdt switch interrupts or transmits the output signal of the first logic level 2 depending on the control of a function program level 7.

A 2-bit binary counter 8 supplies control pulses for at the output two transitions from logic level 1 to logic level 0 at its input.

The output pulse of the binary counter 8 is via a buffer transistor 22 is used to switch off a relay R2 for ejecting the cassette, so that with each output pulse of the

Counter

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Counter 8 the cassette is ejected.

Furthermore, the output pulse of the binary counter 8 can also be used to switch off a motor 23 via a driver transistor 24 Ver-Wend Find.

Two switches S5 and S6 are assigned to the positioning of the cassette, the switch S 5 is closed with the beginning of the insertion of the cassette, and the energization of the relays Rl and R2 causes. On the other hand, the switch S6 is closed as soon as the cassette assumes the operating state, in order to activate it of the motor 23 to trigger.

A lamp 25 is assigned to the output of the detector 1 and indicates the correct advance of the tape.

The functioning of the electronic system according to Fig. 1 is as follows:

When the function program stage 7 is switched to the position automatic return flow, the switch stage 4 is closed and switch stage 5 is open. At the same time, the level 6 switch is in position I. Under these conditions, as soon as the cassette is inserted, switch S5 is closed and the return relay R1 and the ejector relay R2 are energized.

The output signal of the detector 1 assumes the logic level, while the output signal of the logic level 2 takes on the logic signal level 0 is because the switch S6 is open. The motor is not excited in this state, i.e. it is stationary Disk 20 is still held, so that at the output of the monostable multivibrator 3, the logic signal level 0 and

at the

10 SB5P-1957

The logic signal level 0 is also effective at the output of the binary counter 8. The relays Rl and remain in this state R2 excited.

As soon as the cassette reaches the operating position, the switch will S6 is closed and the motor 23 ″ is set in motion. The output signal of the detector 1 thus assumes the logical signal level 1, while the output signal of logic level 2 remains at logic level 0 because switch S6 is closed. In the circuit after logic level 2, everything remains unchanged, so that the cassette is played according to program I. At the end of program I, the tape reaches the cassette the end position and the disc 20 remains. The output signal of the detector 1 thus assumes the logic signal level 0 and, since the switch SG is closed and thus the voltage VB2 is different from 0, the output signal also changes of logic level 2 and assumes signal level 1. This triggers an output pulse on the monostable multivibrator 3, which releases the excitation of the return relay Rl and thus triggers the return of the belt.

At the output of the binary counter 8, the logic signal level 0 is still present, so that the motor 23 and the ejection relay continue to run R2 remains excited.

At the end of program II, the disc 20 is stopped for the second time and an impulse from the nionostable multivibrator 3 for triggering the drop in excitation for the return relay Rl delivered. Because at this point the output signal on the binary counter 8 changes to the logic signal 1, the motor 23 remains

stand

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stand and the excitation of the ejector relay R2 drops out, so that the Ejection of the cartridge is caused.

If function program level 7 is set to "individual program" is, the switch stage 4 is open and the switch stage 5 is closed. Furthermore, the spdt switch takes switch stage 6 position II. In this circuit configuration, the binary counter 8 is switched off, so that the cassette at the end of each Program is ejected. In the event that function program level 7 is in the position for a continuous program ", the switch stage 4 is open and the switch stage 5 is closed, whereas the spdt switch of the switch stage 6 assumes position II. With this circuit, a continuous playback mode of the cassette is maintained, with the program alternating 1 and program 2 run one after the other in an unlimited sequence. A circuit diagram of the electronic system shown in FIG is shown in Figs. Here, the blocks shown in Fig. 1 are indicated by dashed lines and with the same Provided with reference numerals. The pulse diagrams shown in FIG. 4 serve to better explain this circuit.

The detector 1 for detecting the rotation of the disk 20 comprises a capacitive sensor 25 'as described in the German patent application P 29 06 929 was described. The circuit includes an oscillator 26 that operates at a frequency of about 100 kHz oscillates and is made up of three NOR gates of the CMOS type is. A first detector circuit 27 is also provided, which detects the modulation impressed by the capacitive sensor 25 '. A second detector circuit 28 supplies a logic output on the output side Level 1, which corresponds to the voltage VB2 if

one

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a modulation is present and a logic signal level 0, which corresponds to the ground signal when no modulation is present is.

The monostable multivibrator 3 is constructed from a linearly integrated circuit 29 of the 555 type, which is positive on the output side Delivers square-wave pulses, the duration of which depends on the capacity of the capacitor 30 connected to pin 6 is determined, if there is a negative pulse of any duration at the input.

This pulse is received from a differential circuit, which is made up of a NAND gate 31 and an RC network consisting of the capacitor 32 and the resistor 33. At the entrance of the NAND gate 31, a positive step voltage is applied.

In Fig. 3, the 2-bit binary counter 8 is shown, which consists of two NOR gates 34 and 35, which are connected as SR flip-flops and work on a NOR gate 36 on the output side.

A pulse of type 101, which is sent to the binary counter via input C. 8 acts, is differentiated and then the first negatively differentiated impulse is eliminated, while the second positively differentiated Pulse on from the output signal at terminal H of the flip-flop 34-35 triggers and the signal level of the logic 1 to logical 0 changes.

At this point in time, the output signal from the NOR gate remains which was at the logical signal level 1 at this signal level lie. A change to signal level 0 only occurs if the input, i.e. connection C, receives a new pulse

receive

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Will be received.

The function program stage 7 comprises a three-position switch Sl, whose switching shaft can be moved in the axial direction against a spring in order to close a switch S2. In a corresponding manner, the switch S3 is also activated by an axial displacement of the setting button for the fast Belt run actuated.

In the position of the three-position switch shown in FIG The "automatic return" program is set. The middle position is the "continuous program" function and the "Individual program" function is assigned to the left position. By pressing in the switching shaft of switch 1, As already mentioned, the switch 2 is closed, so that the reversal of the transport direction of the tape can be switched by hand, because the return relay Rl is in the non-excited state. When the switch S3 is closed, the excitation of the ejection relay R2 be turned off so that the cassette can be ejected by hand in this way.

The mode of operation of the circuit is described with reference to FIG.

In the "automatic return" operating position, the time after inserting the cassette switch S5 is closed. This point in time corresponds to on the time axis of the diagram according to 4 the time t0. At this point in time, the output of the detector 1 and the output of the logic level 2 is the Signal level 0, whereas a logic 1 acts at the input of the integrated circuit, namely at pin 2, which means that the return -

relay

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relay Rl is energized. The logic signal 1 acts at the output of the flip-flop 34-35 because of the desired preference when switching. The output signal of the binary counter 8 is at the logic signal level 0, so that at the node I a logical 1 is effective. This energizes the ejection relay R2. The motor 23 is stopped because the switch S6 is opened and the supply voltage VB2 is not applied.

As soon as the cassette assumes the operating position at time ti, switch S6 is closed so that detector 1 assumes signal level 1 at the output. Signal level 0 is retained at the output of logic level 2. This not change all the logical level 2 switching stages downstream their switching state other than the motor 23 starts to run, j ₅ as nunr ore, the supply voltage VB2 is effective.

Program I.

At the end of the strip passage at time t2, the output 2Q of the detector 1 goes to the logic signal level 0 and switches the Output of logic level 2 to signal level 1. The transition from signal level 0 to signal level 1 at the output of this logic level 2 causes the start of a pulse for the drop in excitation of the return relay Rl, which up to the point in time t3 works. The signal level at the output of switch stage 4, i.e. at switching point C, changes accordingly, but the flip-flop becomes 34-35 not activated. The eject relay R2 and the motor 23 thus remain in the excited state, which continues to run.

The drop in excitation of the return relay Rl causes the mechanical

standby

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15 SB5P-1957

Ready for tape transport in the opposite direction. If this mechanical readiness occurs at time t4, the disk 20 begins to rotate again, so that the output of the detector 1 returns to logic signal level 1 falls back and the output of logic level 2 assumes the signal level. This also results in switch stage 4 at the output the logic signal level 1, which controls the flip-flop 34-35 and switches to signal level 0 at output H. Since the signal level 0 is present at the output of the switching stage 4 and the output of the NOR gate 36 of the binary counter 8 is at the signal level 1 remains, the switching point I also remains at the signal level 1 lie, so that the motor 23 and the ejection relay R2 remain in the energized state.

Program II is now running.

At the end of the belt run at time t5, the output of the detector 1 again assumes the logic signal level 0 and triggers logic level 1 at the output of logic level 2, i.e. at switching point D. This creates a control pulse caused for the monostable multivibrator 3, which causes the drop in excitation for the changeover relay Rl up to time t6. At switching point C, i.e. at the output of switch stage 4, signal level 1 changes to signal level 0, which means on Output of binary counter 8 triggers a switchover to signal level and at switching point I a switchover to signal level 0 is triggered will. This signal change causes the ' Motor 23 and the mechanical readiness to release the ejector relay R2, which, however, remains in the energized state, since the Switch S4 is open.

This

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This switch S4 is sensor-controlled depending on the position of the magnetic head. The switch is open when the magnetic head is inserted into the cassette and takes the open one State on when the magnetic head is completely outside the cassette. The drop in excitation of the changeover relay Rl and the Stopping the motor 23 causes the carriage with the magnetic head to slide out, and the switch S4 at time t7 closes.

2Q Closing switch S4 causes the excitation drop for the Eject relay R2, so that the cassette is shifted from the operating position. At the same time, the switch S6 is at the point in time t8 open.

Opening this switch S6 changes the output logic level 2 in switching point D to logic signal level 0, as well as at the output of switch level 4 in the switching point C to signal level 1. At the same time, there is also a transition to signal level 1 and a new one at switching point I. Excitation of the ejection relay R2. The motor 23 does not experience renewed excitation, since the switch S6 is open and thus the supply voltage is not present, i.e. VB2 is 0. The re-excitation of the ejector relay R2 does not cause any problems at this point the cassette has already left the operating position Has. In this way, the ejector relay R2 is already prepared for the new insertion of a cassette.

When the cassette is removed from the device, the switch S5 opens at time t9, whereby the entire circuit is in the Hibernation falls back.

in the

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In the "continuous program" operating state, the switch S1 assumes its middle position, with a logic signal level 0 is effective both at the first input of the switch stage 5 and at the first input of the NAND gate 37 in the switch stage 6. With this circuit configuration, the ejection relay R2 held continuously, so that the motor 23 runs continuously and through this only the drop in excitation with each stop of the disc 20 of the changeover relay Rl is triggered.

In the "single program" mode of operation, the switch S1 is in the left switch position according to FIG. 3, whereby the first Input of the NAND gate 37 in the switch stage 6, the signal level 0 and signal level 1 is effective at the first input of switch stage 5. As a result, the control pulse can switch the switch stage 6 can only be reached via switch stage 5, which is always the case when the disc 20 stops. From it the result is that at the end of each program run, the motor 23 stops and the cassette is ejected.

When switch S2 is closed, only the changeover relay is activated Rl causes an excitation drop control and thus the manual control for reversing the transport direction of the Tape released.

When the switch S3 is closed, the motor 23 stops, whereupon the cassette is ejected when the magnetic head has left the cassette. Furthermore, the switch Si is caused to close.

From the explanation of the circuit according to FIGS. 2 and 3 results

themselves

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that with this circuit all control functions for a reversible Belt control can be realized in an advantageous manner. The circuit described can be simplified with appropriate simplification can also be used for any belt controls, even if these do not provide for reverse operation, as long as relays for the actuation can be used. The circuit described works in the same way with others than those described Circuit parts can be built as long as care is taken that the described switching functions with equivalent Elements are executed.

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Claims (4)

PATENT CLAIMS Electronic control circuit for tape recording and
Tape playback devices with forward and reverse operation, where
the mechanical actuation of the reversal of the transport direction of the tape takes place with the help of a relay, thereby
marked, - That a detector (1) for the tape disk rotation (disk 20) on the output side the logic signal level 0 or 1 as a function from the rest position or the rotation of the belt disk (20), - That the detector (1) is followed by a logic stage (2) which, on the output side, has the logic signal level 0 or 1 delivers, depending on whether the belt disc (20) was held in place after a previous running operation or an idle operation will, - And that a monostable multivibrator (3) on the output signal the logic level (2) responds and on the output side for every transition from signal level 1 to signal level 0 90 9850/083 * SB5P-1957 a control pulse to the relay (changeover relay Rl) for reversing the tape transport direction supplies, with a The tape transport direction is always switched when the tape plate (20) is in an end position of the tape Standstill comes. 2. Electronic control circuit according to claim 1, characterized marked, - That an ejection relay (R 2) is present, the me chanical Eject the cartridge depending on one Control pulse that controls a 2-bit binary counter (8) depending on the output signal of the logic level (2) delivers when a transition from signal level 1 takes place at signal level 0, - and that after two switchings of the tape transport direction the cassette is ejected. 3. Electronic control circuit according to claim 2, characterized in that - That for the drive motor (23) a driver transistor (24) is present, the base of which is connected to the output of the binary counter, and its emitter-collector path is in series with the motor (23), - and that the excitation of the motor drops when the cassette is ejected. 4. Electronic control circuit according to one of claims 1 to 3, characterized in that - That a function program stage (7) is present, which acts on a first and third switch stage (4, 6) and 909850/0894 SB5P-1957 lies between the output of the logic level (2) and the input of the binary counter (8), - that a spdt switch from the function program level (7) is actuated, which with one changeover contact to the output of the logic level (2) and with the other changeover contact is connected to the output of the binary counter (8) and its switching arm with the base of a buffer transistor (22) for controlling the ejection relay (R2) and also with the base of a further buffer transistor (24) is connected to control the motor (23), wherein When the first switch stage (4) is open, the output of the first logic stage (2) is on the switching arm of the spdt switch, so that the cassette is ejected in response to each reversal of the tape transport direction. 5. Electronic control circuit according to one or more of claims 1 to 4, characterized in that - That a second, also from the function program stage (7) operated second switch stage (5) is available, which is between the output of the logic level (2) and the second changeover contact of the spdt switch, - and that in the open state of the second switch stage (5) the operating mode? 'continuous program "is effective if the Switching arm of the third switch stage (6) is on the second changeover contact. 6. Electronic control circuit according to one or more of claims 1 to 5, characterized in that - that the 2-bit binary counts (8) two NOR gates (34,35) contained in an SR flip-flop circuit, 909850 / 089A 4 SB5P-1957 - That another output-side NOR gate with his first input at the input of the binary counter (8) and with its second input at the inverting output of the SR flip-flop circuit is located, - And that a differentiation circuit between the input of the binary counter (8) and the S input of the SR flip-flop circuit (34, 35) is switched and the negative pulses resulting from the differentiation are suppressed and that the R input of the SR flip-flop circuit (34, 35) with the reset pulse at the moment of switching on the System is acted upon. 909850/0894